The Ombudsman has ordered the release of statements given to police by outgoing ACT MP John Banks, ruling it is in the public interest.

But the statements would not be handed over until after Banks' trial over allegations he knowingly filed a false electoral return following his failed 2010 bid for the Auckland mayoralty.

Media and Labour Leader David Cunliffe's office both requested Banks' statements after irregularities were alleged in respect of electoral funding donations for Banks' mayoral campaign.

His trial, set down for May, follows a police investigation over whether Banks knew the sources of a $15,000 donation from SkyCity and two $25,000 cheques from internet entrepreneur Kim Dotcom that were declared as anonymous.

In a decision released today, Ombudsman Ron Paterson said police were right to refuse some parts of the request, but not to withhold the statements in full.

In their response to the request, police said public interest had to be balanced with the privacy of the person, particularly if allegations remained unproven.

"However, [the] police accepts that there is also a very high public interest in confirming that a thorough investigation was completed and that appropriate decisions were made in relation to a complaint about a public and democratic process," a police statement said.

Banks had previously objected to his statement's being released by police.

Labour associate security and intelligence spokesman Grant Robertson said Labour was right to call for the release of the documents.

"The Ombudsman's ruling today proves Labour was right to pursue the release of this information. This is a matter of high public interest involving a sitting electorate MP."

He said Prime Minister John Key should be asking to see the documents as well.

Police have already released the executive summary of Detective Inspector Mark Benefield's criminal assessment report, along with statements of witnesses who authorised disclosure.

Paterson said that at the time of the request, Banks also had a reasonable expectation of privacy, because he had not at that stage been charged.

But because he was an MP he should have forgone some of that expectation.

"I am not convinced that a Member of Parliament who is interviewed by the police, with a Queen's Counsel present, about alleged irregularities in respect of electoral funding donations when campaigning for mayor of New Zealand's largest city, can have a high expectation of privacy in their statement, irrespective of whether charges ensue," he said.